<p>
  {{mybody | slice:0:3 }} <br>
  {{mydate}} <br>
  {{mydate | date:'yyyy-MM-dd'}}
</p>

<button class="btn" (click)="changetitle()">改变title</button>

<ul>
  <li *ngFor="let item of list; let i = index">{{i+1}}-{{item.name}}</li>
</ul>

<div [ngSwitch]="switchOpt">
  <p *ngSwitchCase = "'a'">aaa</p>
  <p *ngSwitchCase = "'b'">bbb</p>
  <p *ngSwitchCase = "'c'">ccc</p>
  <p *ngSwitchDefault>default</p>
</div>
